Project Summary/Abstract The University of California, San Francisco (UCSF) is requesting funds for the purchase of a multiplexed ion beam imaging microscope (MIBIscope) from Ionpath, Inc. MIBI is a transformational new technology that enables highly multiplexed measurement of proteins in histological tissue sections, but it is currently unavailable at UCSF. The MIBIscope builds on the success of mass cytometry (i.e., CyTOF), a technology that uses metal-tagged antibodies and mass spectrometry to routinely quantify over 40 proteins in single cells. However, rather than measuring the abundance of these metal tags on cells in liquid suspension, MIBI quantifies these reporter ions directly off tissue on a microscope slide with 250nm resolution. This technology thus provides the investigator with spatial information about where cells reside in tissue, how they are organized into neighborhoods, and even where molecules of interest are localized within cells. The MIBI platform is the only technology that enables imaging of up to 54 antibodies simultaneously at 250nm resolution. The rationale for this proposal is the current lack of MIBI technology at UCSF and the significant number of research programs and specific projects that would significantly benefit from its availability. There are 33 scientific projects by 26 investigators from 14 different UCSF departments providing justification for funding. Consistent with the anticipated use by a diverse number of research groups, the MIBIscope will serve as a shared resource with a projected usage of nearly 5000 hours per year. A broad diversity of projects, ranging from basic science to clinical trial correlative studies, would utilize the MIBI technology. UCSF has recently invested $2M in a renovation project that supported the implementation of mass cytometry in a BSL2 facility for both pre-clinical and clinical studies. As a result, the infrastructure for conjugating antibodies to heavy metal isotopes is already fully functional and established as a service at UCSF. This will greatly facilitate the implementation of MIBI technology by providing a resource for the generation of custom reagents. UCSF investigators have also developed a novel recombinant antibody screening and production platform that will be uitilized for the development of new MIBI reagents. Moreover, technical staff at UCSF have developed the expertise required to effectively manage mass cytometry studies in a shared instrument setting, and these individuals are also prepared and eager to facilitate the implementation of MIBI technology. UCSF investigators serving on the proposed advisory board have extensive expertise in quantitative image analysis and single-cell analysis, which will ensure that researchers utilizing MIBI will have support as they analyze and interpret their resulting data. Users will have access to continued training, support, education courses, and monthly user group meetings, following the model established for mass cytometry at UCSF.